Internal combustion engine



April 11, 1944. o. E. SZEKELY 2,346,463

I INTERNAL COMBUSTION ENGINE Filed Sept. 25, 194i 4 Sheets-Sheet 1INVENTOR 0770 E. JZE/I'ELY fr lag/k410i, 8 %MM 910 H/S ATTORNEYS April1; 1944. o. E. SZEKELY I INTERNAL COMBUSTION ENGINE 4 Sheets-Sheet 2Filed Sept. 25, 1941 INYENTORQ v 0770 E SZL-KELY BY 6 I 9,, mi/ H/sATTORNEYS April 11, 1944. Q s L 2,346,463

INTERNAL COMBUSTION ENGINE I Filed Sept. 25,1941 4 Sheets-Sheet 3 H SATTORNEYS April 11,1944. Q EJ K I 2,346,463

INTERNAL COMBUSTION ENGINE F iled Sept. 23, 1941 4 SheetsSheet 4INVENTOR 077 0 E, JZEhELY H '5 ATTORNEYS Patented Apr. 11, 1944 INTERNALCOMBUSTION ENGINE on. E. Szekely, Philadelphia, Pa, assignor to MartinMotors, Inc., Dover, Del., a corporation of Delaware ApplicationSeptember 23, 1941, Serial No. 411,956

6 Claims.

This invention relates to internal combustion engines, and especially tointernal combustion engines of the compression-ignition type havingmechanical injection of liquid fuel.

The general object of the invention is to provide an improvedconstruction and arrangement of such engines by which thecharacteristics of the explosive charges within the engine cylinders areimproved through providing greater uniformity in the charge received byeach cylinder and by the same cylinder on successive strokes, andthrough better mixing of the charged air and fuel spray.

The invention aims to provide a construction and arrangement whereby thecharging air is evenly distributed between the various cylindersof theengine so that all of the cylinders are uniformly charged with the samequantity of air, even when the engine is of comparatively large physicaldimensions, so that each cylinder can be adjusted to produce maximumpower.

The invention also aims to provide a construction and arrangement whichafiords cooling of the charging air as well as uniform distributionamong the various engine cylinders.

Further, the invention aims to provide a construction and arrangementwhich produces a more dynamic rotation of the charged air within thecylinders which efl'ects a more thorough and intimate mixing of the airand the injected fuel spray.

, A still further object of the invention is to provide these featuresin an engine construction which embodies compactness and lightness ofWeight.

For a consideration of what I believe to be my invention, attention isdirected to the accompanying drawings and the following description andto the claims appended thereto. The invention is illustrated inconnection with an internal combustion engine of the V-type, but it isto be understood that it is not, necessarily, limited thereto. Theinvention is also shown as being applied to an engine in which thecharging air is received into the cylinders at the ends thereof nearestthe crank shaft. It is to be understood, however, that it can also beused with engines where the air is delivered to the cylinders at or neartheir outer ends. I

In these drawings:

Fig. 1 is a. view partly in central longitudinal vertical section, takenon the plane indicated by line i---! of Fig. 2, and partly in sideelevation, of an internal combustion engine embodying the improvementsof my invention;

Fig. 2 isa vertical transverse section taken on the plane indicated bythe line 2-2 of Fig. 1;

Fig. 3 is a developed horizontal section taken on the planes indicatedby the broken line 33 of Fig. 2 showing the arrangement of'the air inletchambers and ports;

Fig. 4 is a plan view of the engine with the parts above the line 4-4 ofFig. I removed, this view being drawn to a smaller scale; and

Fig. 5 is a fragmentary view drawn in isometric projection to illustratethe entry of the charging air into a cylinder.

Referring now to the accompanying drawings, the V-type engineillustrated has two banks of cylinders A and B, each having fourcylinders, the cylinders of bank A being indicated generally by numeralsl, 2, 3 and 4, respectively, and the cylinders of bank B by numerals 5,6, l and 8, respectively. The crank shaft is indicated at 9 and isprovided with four double cranks with suitable bearings in the engineframe as indicated, for example, at IO, M and i2. Each of the doublecranks is operatively connected with. two pistons operating in cylindersof opposite banks as is customary in V engines Thus, for example,referring to Figs. 2 and l, the piston iii of cylinder 2 is connected byconnecting rod I4 to crank l5 and piston l6 of cylinder 6 is con- 08having air admission ports l9 and exhaust ports 2t. Inlet ports 59comprise a circular row of ports arranged in spaced relation to oneanother and extending entirely around the circumference of the sleeve.Exhaust ports 20 are similarly arranged. Both sets of ports cooperatewith similar ports in the cylinder liner and cylinder block in the usualmanner, scribed later on.

The sleeve valve I8 is reciprocated by means of an eccentric 2|cooperating with which is an eccentric strap 22 which is pivoted at 23to an as will be deextension 24 secured to the lower end of the sleeve.The construction of these sleeve valves l8 and their operating mechanismis the same for each of the cylinders. It will be understood that whilethe sleeve valve construction is preferred,

In the present engine the sleeve l8 reciprocates 'in a cylinder liner 25which is removably secured in the cylinder block but the cylinders maybe integral with the cylinder block if desired. Surrounding thecylinders within the cylinder blocks are the usual passages 26 for thecirculation of cooling liquid. such as water. It will be understood thatthe cooling system includes the usual radiator, pump and suitableconnections, all of which are not shown.

The cylinders are closed at their outer ends by means of cylinder headsor covers 21 which extend for some distance into the sleeves I8, andhave bolt flanges for securing them to the cylinder blocks. The coolingwater is preferabl circulated through these cylinder heads as well asaround the cylinders. Each cylinder head 21 is provided with one or morefuel injection valves 28 through which'the fuel is sprayed into thecharge of highly compressed air within the cylinder in timed relation toeach inward stroke of the piston, the engine illustrated being or thetwocycle type.

A row of exhaust ports 29 is arranged in the cylinder liner 25 justbeneath the lower end of the cylinder head, 21 to cooperate with theexhaust ports 20 f the sleeve valve. These ports open into an annularexhaust chamber 30 to which an exhaust pipe connection 3| is secured onthe outside of the cylinders of each bank.

A row of charging air inlet ports 32 is arranged in the cylinder blockaround the lower portion of each cylinder liner 25 to cooperate with theair admission port I9 of sleeve valve l8 so as to admit charging airinto the cylinder during the time that the piston is near theouter (orlower) end of its stroke. These ports 32 open into an air inlet chamber33 surrounding the cylinder and are of particular construction whichwill be described in detail later on.

In accordance with one of the features of my present invention, anelongated charging air supply chamber 34 is arranged longitudinall ofthe engine and disposed'between the two banks of cylinders A and B. Thebottom surface 35 of this chamber is somewhat above the level of thecharging air admission ports 32. The side walls ,36 extend upwardly fromthe bottom in substantially parallel relation and in close proximity tothe cylinder banks A and B. The top of the air supply chamber 34 ispreferably somewhat below the top of the cylinder block as indicated inFig. 2.

Opening out of the lower portion of air supply chamber 34 and preferablyopening out of the bottom wall 35 thereof are a plurality of passages3'! preferably rectangular in form, as shown in Fig. 4, and constitutingair inlet opening for admitting air from the Supply chamber 34 to therespective air inlet chambers 33 for each of the engine cylinders. Theair inlet openings or passages 31 to the various cylinders aredistributed over the area of the bottom of suppl chamber 34, as may beseen in Fig. 4.

front of the air compressor and the air outlet from the compressor isabove and is indicated by numeral 42.

Inasmuch as the volume of air required by the engine is comparativelylarge and since the'compressor 39 is located at one end of the engine,the distribution of the air so that each of the 8 cylinders will becharged uniformly, presents something of a problem. In addition, the airis compressed to about 10 lbs. per sq. in. and the heat of compressionis substantial and raises the temperature of the air some 110 F., sothat if the temperature of the air at the intake of the compressor is 80F., the temperature of the air in the outlet 42 of thecompressor isabout 190 F. If the air is charged into the engine cylinder at thistemperature, it will disadvantageously aifect both the main coolingsystem of the engine and the proper rate of temperature rise of thecharged air, on the compression stroke. and hence the proper combustionof the fuel,

within the engine cylinders.

shown in Fig. 1. Any convenient source of cool- In order to obviatethese difflcultles there is provided on the top or the air-supplychamber 34 an air cooling heat exchanger which is indicated generally bynumeral 43. This heat exing'liquid may be used.

The tube bundle is arranged within a suitable casmg 50 flanged at bothbottom and top and both the tube bundle and the casing extend the entirelength of air supply chamber 34, casing being bolted, as shown in Fig.2, to a flat rim 5i which extends around the periphery of the mouth ofair supply chamber 34. The walls of casing 50 are parallel, the entranceto the air passageway of the heat exchanger havmg substantially the samearea as the mouth of the air supply chamber, so that air may bedelivered from the air supply compressor 38 simultaneously toallportions of the upper surface of the tube bundleof the air cooler. Thisair is conveyed from the outlet 42 of the air compressor by means ofa/conduit 52 which is bolted to the flange at the upper end of casing50. Conduit 52 comprises a tubular elbow portion 53 which is connectedto the outlet 42 of the air compressor and a hood-like portion 54 whichdelivers the air to the intake of the air passageway of the heatxchanger. Preferably the outer surface of the conduit 52 is providedwith heat radiating flanges 55 for the purpose of assisting in removingheat of compression imparted to the air.

In view of the high velocity of the impeller 39 of the air compressor 38the air enters the elbow portion 53 of conduit 52 at a very highvelocity, in the neighborhood of 60,000 feet per minute. .However, dueto the great enlargement of the area of the hooded portion 54 of conduit2 55 and to the resistance of the multiplicity of small air passagesformed by the cooling tubes 44 and fins 45, this velocity is greatlyreduced when the air enters these cooling passages of the air cooler.Due to the resistance of the multiplicity of air passages of the aircooler there is a pressure drop of about 2 pounds in passing through thecooler so that the pressure in the air supply chamber 34 is about 8pounds per square inch.

The temperature reduction in passing through the air cooler isapproximately the same as the temperature rise due to heat ofcompression in the compressor 38 so that the temperature of the air insupply chamber 34 is about the same as that of the outside air which wasassumed as 80 F. Hence the air delivered to the engine cylinders fromsupply chamber 3t, although at a pressure much higher than that of theatmosphere; has a temperature which is about the same as the atmospherictemperature.

Consequently the rate of temperature rise during the periodofcompression in the engine cylinders is affected by the increase incharging pressure. Also due to the drop in pressure of the air inpassing through the multiplicity of restricted passageways of the heatexchanger and also because of the possibility of free transfer or flowof air between various portions of the supply chamber 34, the air isdistributed uniformly among the 8 cylinders of the engine so that ateach stroke each cylinder receives substantially the same quantity ofair.

In order to improve the combustion characteristics of internalcombustion engines of the compression ignition type it has heretoforebeen proposed to introduce the scavenging and charging air throughtangentially arranged ports so as to produce a whirling action, orrotation, of the air within the cylinder,-and advantage has been takenof the persistence of this motion .of the air after compression andduring the injection of the fuel, to assist in mixing the fuel spray andair.

In engines as heretofore constructed, however;

the motion of the scavenging and charging air outside of the engineports was stopped by the closing of the ports. Therefore, at eachopening of the ports this air had to be set in motion before it couldcommence to enter the cylinder,

and since air possesses considerable mass and inertia. and since theperiod of time elapsing between the opening and closing of the airadmission ports, in high speed engines is a small fraction of a second,the overcoming of the inertia of the air has a tendency to reduce to agreater extent than has heretofore been appreciated both thedynamicefiect of the rotatin air and the quantity of air entering thecylinder for each charge.

In accordance with another feature of my.

present invention this difficulty has been overcome through theprovision of a construction by which the air adjacent the inletsor airadmission ports is caused to remain rotating around the ports during theintervals when the admis- Referring now to Figs. 3, 4 and 5 of theacoutside wall 56 so as to gradually reduce the cross sectional area andequalize the distribution of the air to the ports 32. Thi wall t8 iscontinued around the engine cylinder until it intersects the wall of airpassage 31 at a point 5] which is spaced radially outward from the outeredges of ports 32 so as to leave an air passage at this intersection. Inthis way the air inlet chamber 33 is made to extend continuously aroundthe circular row or ports 32 surrounding the cylinder.

In operation, therefore, the air passing downwardly from air supplychamber 34 into an air passage 31 which is substantially tangent to theboundary of the outer edges of the inlet ports 32, is directed by thisair passage,'by the spirally shaped outer wall 56 of chamber 33 and bythe tangential ports 32 into the cylinder and simultaneously set inrotating motion. Assuming now that the admission ports are closed, as,for example, by the movement of the sleeve valve 88, the air in the airinlet chamber 33 continues to rotate around the cylinder since thisinlet chamber is a continuous passageway extending entirely around thecircular row of inlet ports 32.

Since the interval of time during which the inlet valve is closed,particularly in a two-cycle engine, is so minute, this rotation of theair in the inlet chamber 33 will persist and the air will be rotatingvigorously at the next opening of i the air admission ports by sleevei8. Consequently the air commences instantly to enter the cylinder sinceit is unnecessary to overcome the inertia which the air in this inletpassage would have if stationary.

By means of the present invention there has been provided a constructionand arrangement of internal combustion engine of the compressionignition type in which the charging air is introduced under a highdegree of supercharge, and is distributed with substantial uniformity toall of the engine cylinders, advantage being taken of the action of anair cooling heat exchanger to equalize the distribution of the air, theheat exchanger at the same time removing heat of compression so that theair is supplied to the cylinders at a temperature which does notimproperly affect the rate of temperature rise during the compressionignition stroke.

By this invention also, a construction and arrangement of air inletchamber has been provided by means of which a ring of air surroundingthe inlet ports is maintained in continuous rotation not only during theair admission period but also during the intervals when the inlet portsare closed. This eliminates the necessity to overcome the inertia ofstationary air each time the air admission valve opens, and the dynamiceffect of the incoming air in producing a whirling of the charge isincreased. Thus the compressed charge of air is in more effectiverotation at the period of fuel injection.

By means of these features of the invention, the characteristics of theexplosive charge have beenimproved first by providing uniformity of thequantity of. air supplied to each cylinder and at each successivestroke, by supplying this air at a temperature which permits the properrate of temperature rise on the compression stroke and by providing fora more substantial persistence of air rotation during fuel injection.

It will be understood that many details of the internal, combustionengine illustrated in the accompanying drawings are unnecessary to acarrying out of the invention, and that the particular 4 of cylinders,an air supply chamber extending substantially the length of said bank ofcylinders, an air inlet from the supply chamber to each cylinder, saidchamber having a mouth substantially co-extensive with the chamber, anair cooler secured to said mouth and substantially co-extensivetherewith, a charging air supply pump and a conduit for conveying airtherefrom to said air cooler, the air cooler serving simultaneously tocool the air entering said chamber and to distribute it uniformlythrough the same to said air inlets.

2. In an internal combustion engine, a bank of cylinders, an air supplychamber extending substantially the length of said bank of cylinders, anair inlet from the supply chamber to each cylinder, said chamber havinga mouth substantially co-exte'hsive with the chamber, an air coolerhaving an air passageway and a cooling fluid passageway, said airpassageway being substantially co-extensive with the mouth of the airsupply chamber, a charging air supply pump and a conduitfor conveyingair therefrom to the air passageway of said cooler, said cooler servingsimultaneously to cool the air entering the air supply chamber and todistribute it uniformly through the same to said air inlets.

3. In an internal combustion engine, a bank of cylinders, an air supplychamber extending substantially the length of said'bank of cylinders, anair inlet from the supply chamber to each cylinder, said chamber havinga mouth substantially co-extensive with the chamber, an air coolerhaving an air passageway comprising .a multipliclty of restrictive airpassages of substantially uniform length and distributed uniformlythroughout the area of the air cooler, said air passageway beingsubstantially co-extensive with v the mouth of the air supply chamber, acharging heat of compression being thereby removed from the air enteringthe air supply chamber and the air being distributed uniformly to saidair inlets.

4. In an internal combustion engine. a bank of cylinders, an elongatedair supply chamber therefor, an air inlet from the supply'chamber toeach cylinder, an air cooler having an air passageway substantiallyco-extensive with the area of the air supply chamber and serving as theentrance thereto, said air passageway comprising a multiplicity of airpassages arranged to produce substantially uniform air flow resistancethroughout the area of said passageway, a charging air supply pump and aconduit for conveying air therefrom to the air passageway of saidcooler, whereby heat of compression is removed from the air and the airis distributed uniformly to said air inlets.

5. In an internal combustion engine a bank of cylinders, an elongatedair supply chamber ex tending longitudinally of said bank of cylinders,an air inlet from the bottom of the supply chamber to eachcylinder, anair cooler substan tially covering the top of the air distributingchamber, said cooler li'a'ving an air passageway comprising amultiplicity of small air passages distributed substantially uniformlythroughout the area of said passageway, a charging air supply pump and acondldt for conveying air' therefrom to said passageway. whereby the airis simultaneously cooled and distributed uniformly to said air inlets.

6. The combination of an internal combustion engine having two banks ofcylinders disposed in proximity to one another, a charging air supplychamber extending longitudinally between the two cylinder banks, an airinlet chamber for each cylinder of both banks arranged to receive airfrom the supply chamber, a heat exchanger substantially covering themouth of said air supply chamber, a charging air supply pump, and an airconduit for conveying the air therefrom and delivering it to the heatexchanger through which it passes into the supply chamber, the said heatexchanger serving simultaneously to cool and uniformly distribute theair throughout the length of said supply chamber.

O'I'IO E. SZEKELY.

